package com.ls.nio;

import org.junit.Test;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Date;
import java.util.Iterator;
import java.util.Scanner;

public class TestNonBlockingNIO {
    //客户端
    public static void client() throws IOException {
        //1. 获取通道
        SocketChannel sChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 8080));

        //2. 切换非阻塞模式
        sChannel.configureBlocking(false);

        //3. 分配指定大小的缓冲区
        ByteBuffer buf = ByteBuffer.allocate(1024);

        //4. 发送数据给服务端
        Scanner scan = new Scanner(System.in);

        while(scan.hasNext()){
            String str = scan.next();
            buf.put(("刘帅 "+new Date().toString() + "\n" + str).getBytes());
            buf.flip();
            sChannel.write(buf);
            buf.clear();
        }

        //5. 关闭通道
        sChannel.close();
    }

    public static void main(String[] args) throws IOException {
        client();
    }
    //服务端
    @Test
    public void server() throws IOException{
        //1. 获取通道
        ServerSocketChannel ssChannel = ServerSocketChannel.open();

        //2. 切换非阻塞模式
        ssChannel.configureBlocking(false);

        //3. 绑定连接
        ssChannel.bind(new InetSocketAddress(8080));

        //4. 获取选择器
        Selector selector = Selector.open();

        //5. 将通道注册到选择器上, 并且指定“监听接收事件”
        ssChannel.register(selector, SelectionKey.OP_ACCEPT);

        //6. 轮询式的获取选择器上已经“准备就绪”的事件
        while(selector.select() > 0){

            //7. 获取当前选择器中所有注册的“选择键(已就绪的监听事件)”
            Iterator<SelectionKey> it = selector.selectedKeys().iterator();

            while(it.hasNext()){
                //8. 获取准备“就绪”的是事件
                SelectionKey sk = it.next();

                //9. 判断具体是什么事件准备就绪
                if(sk.isAcceptable()){
                    //10. 若“接收就绪”，获取客户端连接
                    SocketChannel sChannel = ssChannel.accept();

                    //11. 切换非阻塞模式
                    sChannel.configureBlocking(false);

                    //12. 将该通道注册到选择器上
                    sChannel.register(selector, SelectionKey.OP_READ);
                }else if(sk.isReadable()){
                    //13. 获取当前选择器上“读就绪”状态的通道
                    SocketChannel sChannel = (SocketChannel) sk.channel();

                    //14. 读取数据
                    ByteBuffer buf = ByteBuffer.allocate(1024);

                    int len = 0;
                    while((len = sChannel.read(buf)) > 0 ){
                        buf.flip();
                        System.out.println(new String(buf.array(), 0, len));
                        buf.clear();
                    }
                }

                //15. 取消选择键 SelectionKey
                it.remove();
            }
        }
    }
}
